1. Field of the Invention
The present invention relates to finish compositions for fibrous materials, and more particularly to compositions comprised of elastomeric material, a lubricious substance and water which are coated onto the fibers or filaments of materials such as carbon, graphite or silica to protect the materials during weaving or other use which involves bending, abrading and the like.
2. History of the Prior Art
The textile arts have of late been substantially influenced by the development of a variety of fibrous and filamentous strands in the form of yarns, tow, and rovings of high tensile strength, high elastic modulus materials such as carbon, graphite, and a variety of inorganic substances. Because of their strength and refractory capabilities, such materials find use in a variety of applications including aerospace materials, both ablative and otherwise, and in the manufacture of sporting goods. In still other instances the materials are useful as heat shields and other protective barriers such as in welding environments.
In many applications, it is preferred that the fibers, filaments, yarns or tows be woven into a fabric or tape or otherwise interlaced or overlapped such that the strands are in contact with other similar strands or successive turns of themselves. Because of the high moduli, brittleness, and relatively poor abrasion resistance of the strands or the fibers which comprise them, they have been difficult to handle during their processing and weaving into fabrics and tapes. In some cases, poor abrasion resistance remains a problem after weaving because of structural damage to the fabric caused by interstrand or interfilament abrasion within strands due to the normal bending and flexing encountered in essentially all of the fabric end uses. The utilization of the new fibers, yarns, tows, fabrics and tapes in many applications for which there are properties otherwise suited to them, has not been possible because of these disadvantages.
It has been found that the abrasion resistance of certain fibrous materials can be increased by use of a finish composition. One such composition which is disclosed in U.S. Pat. No. 3,501,431, Ross et al., SIZING SYSTEM FOR HIGH MODULUS FIBERS AND METHOD AND APPARATUS FOR APPLYING SAME, is comprised of an elastomer, a lubricious substance and a solvent. The elastomer is chosen from fluorinated elastomers, urethanes and flexible vinyl chloride. While finish compositions such as this have been found to increase the abrasion resistance somewhat, they do not afford sufficient protection against mechanical damage and filament breakage for many applications and particularly in the case of certain fibers. In still other applications dusting and linting of the fibrous materials may not be reduced to reasonable or acceptable levels by such finish compositions. Further disadvantages reside in the fact that many such prior art finish composition are flammable, give off considerable smoke and toxic fumes when exposed to high temperatures such as upon removal of the finish or upon use of the material and may not be easily removed from the fibrous material when desired.
Accordingly, it would be desirable to provide an improved finishing system for application to strands of fibers or filaments of frangible material to enable them to be woven or otherwise converted into fabric or tape or to enable them to withstand bending or flexing during use without failing prematurely because of poor abrasion resistance.
It would furthermore be desirable to provide a finish system which is non-flammable, is low smoking and does not give off toxic fumes or other toxic byproducts when exposed to high temperatures and is easily removed from the fibrous material when desired.